When using document-based storage, allow projecting certain properties to columns

This could be handy to allow querying by those columns in particular.

So maybe it could be via an implemented interface that's then used when creating the repository? For example: DocumentRepository.Create<Book, IAddressable>()?

        public static IDocumentRepository<T> Create<T, TProperties>(...)
            where T: class, TProperties
            where TProperties: IDocumentEntity

Where the returned document repository augmented IDocumentRepository<T> with the ability to perform queries, such as:

        public interface IDocumentRepository<T, TProperties> : IDocumentRepository<T>
            where T : class, TProperties
        {
            IAsyncEnumerable<T> CreateQuery(Expression<Func<TProperties, bool>> predicate, CancellationToken cancellation = default);
        }

Note that unlike table repository IQueryable<T> CreateQuery() version, we need to restrict the available properties for querying to the TProperties since not all T properties will be available as columns. So using an expression for the properties and an async enumerable with the full entity type seems the most natural.

Start by locating the document repository creation API and the table repository CreateQuery implementation mentioned in the issue. Compare how repository capabilities are exposed, then determine how projected properties and the proposed constrained async query would fit. Done means the design is settled and document storage supports querying the selected properties as columns.